Note: Descriptions are shown in the official language in which they were submitted.
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3 25032-23
Devlce_for purifylng am ient_alr and_enclosed spaces.
The international application WO 81/00051 published
on 22nd January 1981 discloses an object which is impervious to
liquids and is intended for perfuming ambien-t air or enclosed
spaces, characterized in that it contains a perfuming composition
enriched with substances which may or may not be fragrant and have
low polarity and in that the object has at least one polymeric
wall enabling active fragrant ingredients to be diffused towards
the exterior.
The French patent application FR A 20 91 855, published
on 21st January 1972, relates to a device for the continuous
diffusion of purifying agent vapours, which device comprises a
permeation wall made of macromolecular material, one face of
which is in contact with the volatile purifying agent which
impregnates a fibrous mass covered by the permeation wall.
The French patent application FR A 23 36 9~6, published
on 29th July 1977, relates to a slow diffusion air-freshening
systems which comprises a chamber and a perfume contained in
the said chamber, at least one surface of the said chamber being
a polymer film. Likewise in this system the perfume is impreg-
nated in a support such as silica, talc, glass wool or blotting
paper.
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The US paten-t 3 578 545, published on l.lth May 1971,
relates to a flexible laminated substance releasing a perfume
and comprising a fabric support impregnated with a perfume,
surrounded by a porous plastic film and permeable to perfume
vapours.
The US patent 4 161 283, published on 17th July 1979,
describes a device for continuously diffusing purifying vapours;
the said device comprises an outer wall formed by a polymeric
material enabling molecular diffusion and an impermeable inner
wall. The outer wall is in addition covered with an impermeable
sheet suitable for preventing the diffusion of the active vola-
tile substances during storage.
A similar device is described in the US patent
4 285 468, published on Z5th August 1981.
As the purifying articles described in the prior art
are all constituted by a system comprising a polymeric diffusion
wall, they should have a device for preventing the active
perfuming elements from diffusing into the environment during
storage.
To its end, the international application WO 81/00051
describes a method consisting in applying a Surlyn type
polymeric sheet (origin: Du Pont de Nemours) on the walls,
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through which diffusion normally occurs. This type of polymeric
sheet may adhere by hot weldlng to polyethylene or polypropylene
and be detached just before use. For the same purpose, a further
method consists in using aluminium sheets welded to polypropylene
foam.
A problem arises, however, during extended storage of
such devices before they are sold; owing to the diffusion of the
perfume vapours through the polymeric walls of the packing, an
appreciable loss of the initial amount of the active substance has
been observed In order to overcome this disadvantage, a multi-
chamber device has recently been developed (cf. international
patent application WO 82/02700 published on l9th August 1982). In
a device of this type, the active perfuming substance is kept in a
compartment having walls which are impermeable to perfume vapours
and one join of which may be broken under the effect of external
pressure and subsequently, just before use, when the walls of the
said join have been broken, the solu-tion passes into a compartment
having walls made of a polymeric material permeable with respect to
the perfume vapours which can than diffuse uniformly in-to the
ambient atmosphere.
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A device of this type is highly efficient in use, how-
ever the manufacture thereof requires an improved apparatus to be
produced and a rigorous assembly procedure.
In order to remedy such disadvantages the present inven-
tion proposes a novel solution based on a simple procedure.
The principle on which the invention is based consists
in the direct assembly by welding of a thin layer of paper on the
external wall of the polymeric membrane through which the diffu-
sion of the active substance vapours occurs. This thin paper
layer is then covered with a polymeric material sheet, for example
of the Surlyn type having a polyethylene base, on which a
metal sheet, preferably an aluminium sheet, for example, is
finally welded. A metal sheet of this type constitutes an imper-
meable barrier with respect to the active substance vapours by
preventing their molecular diffusion towards the exterior. Of
course, other materials may also be suitable for this purpose,
provided that they have an adequate coefficient of imperme-
ability.
The present invention therefore provides a device for
perfuming ambient air or enclosed spaces which comprises at least
one chamber containing an active fragrant substance and having at
least one wall made of polymeric material enabling the vapours of
the active fragrant substance to diffuse into the environment the
outer surface of said polymeric wall being covered with a thin
paper layer, said layer being covered with a sheet of polymeric
material to which there adheres a sheet of protective material
impermeable to the vapours of the active substanceO
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By using the device according to the invention, the
active solution may be kept without any losses for extended
periods of time before being used. At the desired moment, the
user could, on the otherhand, easily tear the packing partially or
completely and thus enable the active substance to diffuse towards
the exterior from the chamber.
Embodiments of the invention are shown in the attached
drawings given by way of non-limiting example wherein:
Figure 1 is a transverse sectional view of a filled
device showing one embodiment of the invention;
Figure 2 is a plan view of a second embodiment;
Figure 3 is a plan view showing a series of filled
devices;
Figure 4 is an enlarged sectional view showing a wall
structure;
Figure 5 shows the wall structure of Figure 4 partially
separated; and
Figure 6 is a sectional view showing a further embodi-
ment.
2~ The embodiments of Figure 1 consists in particular ox a
chamber (1) containing the active substance, a permeable polymeric
wall (2), a thin paper layer (3), a polymeric sheet I) and an
outer metal sheet (5), (6) defines a welding or indentation zone.
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8 25032-23
Figure 2 shows a particular embodiment of the device
according to the invention. This embodiment comprises a plurality
of grooves (7) in the impermeable wall or walls, which form the
"cannulae" through which the active substance can infiltrate.
The diffusion thereof is therefore improved.
Figure 3 shows the devices arranged in a row. The user
may tear the protective layers, successively exposing each of the
permeable polymeric walls. In order to facilitate tearing, a tab
(8) may be provided in one corner of the device.
Figure 4 is an enlarged section of the permeable wall
covered with the protective layer: paper (3), polymeric sheet (4)
and metal sheet (5).
Figure 5 shows the same part when stress (a) is applied
on the outer protective layer. In this way the paper layer tears
along the longitudinal axis and, under the effect of the stress
~b), the vapours of the active substance diffuse through the wall
(2) ana the residual paper (3).
For other embodiments reference may be made to the
particular devices disclosed in the prior art. The principle
advantage provided by the device according to the invention
resides not only in the simplicity of its assembly but also in
ihe fact that the tear is effected in a particularly accurate
manner along a longitudinal axis. Since the paper layer may
adhere directly to the permeable polymeric wall by welding, without
an adhesive having to be used, the diffusion of the vapours of the
9 25032-23
active substance is not hampered at all. In addition, it canno-t
be denied that from the aesthetic point of view the solution accor-
ding to the present invention offers many advantages: the tear
in the paper layer leaves the device with a homogeneous surface.
Using paper as an element of the protective layer has
already been proposed in the prior art. ItS use, however, was
restricted either -to containing directly the active substance
taccording to the US patent 3 702 ~77) or to protecting an
adhesive layer placed on the impermeable wall so as to enable the
device to adhere to a vertical or inclined surface (according to
the US patent 4 161 283, column 4, line 30 ff.).
As indicated with respect to the devices of the prior
art, the impermeable walls may be constituted by sheets of poly-
amide, polyester, polyethylene, polypropylene or any other posy-
meric material generally used for the manufacture of packing
sheets.
The permeable wall is, however, to be constituted by
the same materials described in the prior art of in this
respect the international application 81/00051).
As regards the nature of the paper forming the layer
which can be torn, it may consist of natural or artificial fibres
or mixtures ox the two. These products are commercially available
and 47251/1 or 46674 of the Balsthal firm (Balsthal, Switzerland)
may be cited by way of example. A crêpe type of tissue paper is
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thoroughly suitable. The thickness of the paper layer obviously
affects the speed of diffusion of the active vapours. However,
this factor is not decisive. We have been able to observe that
figures between approximately 20 and 100~ were perfectly
satisfactory. The weight of the paper per unit area may be between
20 and 100 gr/m2.
Evidently, both the device according to the invention
and the chamber of this device containing the active substance may
be manufactured in a wide variety of shapes so as to satisfy
functional and aesthetic criteria. For this purpose, the person
skilled in the art may devise solutions appropriate to the
particular uses which are to be studied.
The device according to the invention may, for example,
be used in a casing in which this same device could slide as a
function of the portion of the surface of the permeable wall which
is required to be used, so as to regulate the speed of diffusion.
The principle on which the present invention is based
may be used in ways other than what described above in the field
of ambient air purifiers. Such a principle may be extended to
the production of hermetic closures for all types of containers
which need to be opened after a storage period. my way of
example there may be cited receptacles containing foodstuffs such
as yogourts or custards. Containers of this type, generally made
of plastics material, are principally closed by means of a lid
consisting of a metal sheet. Under the effect of the welding it
is often difficult to open the lid and it may even tear under the
11 25032-23
stress exerted during opening. A disadvantage oE this type can be
eliminated in a device having a lid Eixed by welding to a container,
whose contact join with the said lid comprises a thin layer of
paper to which the lid adheres. Figure 6 shows an example of the
use of such a device. When a stress (_) is exerted in order to
open it, there is a uniform transverse tear along the paper layer
( _ )
